Accessing out-of-bounds from an array in JS results in `undefined` being returned (instead of e.g. throwing an exception), so it is safe in that sense. My idea here was that the return value of GLEW.errorString would be checked, and that function would return null when an out-of-bounds integer was passed, which is then checked here with `if (string == null) return 0;` or similar without caching empty values here. This way the callers of GLEW.errorString don't need to codify which error codes exist, but the function GLEW.errorString will tell that to the caller by either returning a valid string, or null.